application Ser. No. 10/522,805 describes a methodology for performing analog-to-digital conversion and a few possible circuit implementations of said methodology. Said methodology can be implemented with two modes: “Charge-to-Frequency” or “Charge-Subtraction”, and “Voltage-to-Time” or “Voltage-Extrapolation”, and is characterized by:                (a) The input of the ADC is connected to the source signal (Vin(t)), without “Sample and Hold” (S&H) capacitors interposed, therefore being exposed to variations of the source signal, without time integration;        (b) The analog and digital components through which the source signal (Vin(t)) is processed to generate the binary stream, and also those components implementing a feedback loop from the output to the input of the comparator, are all controlled and/or monitored asynchronously;        (c) The output of the comparator, is connected to an asynchronous n-bit digital counter thereby asynchronously registering changes of the state of the output of the comparator;        (d) A feedback loop between the output and the input of the comparator, is routed through an asynchronous path of a digital control unit, thereby enabling asynchronous resetting of the input components;        (f) Because of (a), (b), (c), and (d), the process of generating a stream of binary data at the output of the digital counter is entirely asynchronous on whether a source signal (Vin(t)) exists, and is larger than a voltage reference (Vref), which is itself programmable;        (g) Managed bandwidth, balancing the speed of conversion and the number of bits, through the programmability of the voltage reference (Vref) controlled by a digital controller unit;        
The present invention describes a new implementation of the methodology introduced in application Ser. No. 10/522,805, resulting in more compact circuitry, capable of operating in multiple modes. The versatility of the new ADC will be applied to CMOS image sensors comprising a matrix with avalanche pixels, resulting in novel capabilities for image sensing and formation.